The American legal system, like most legal systems, has its good and its bad points. Let us look at some of the most important of each.
The main good point of the American legal system is that, in criminal law, people have to be proven guilty beyond a reasonable doubt. This places a very strong burden of proof on prosecutors. This is a good thing because it makes it harder for innocent people to be convicted.
Another good point is that it is an adversarial system. This means that people on each side of a case get to have their own lawyers to fight for them. Any defendant, then, can have a lawyer whose only duty is to represent the client. That lawyer will then do everything possible to get them acquitted.
A final good point is that the system limits the sorts of evidence that can be used against criminal defendants. Police are not allowed to use evidence found in illegal searches and seizures in court. Defendants cannot be made to testify against themselves in court. People cannot present hearsay evidence against defendants. All of these things make the system fairer.
The main bad point about the American legal system is that it is biased in favor of wealthy people. Because our system is an adversarial system, the quality of the justice you get depends a lot on the quality of the lawyer you get. Many, many defendants are too poor to afford good lawyers. This means that they can be convicted of crimes when a rich person with good lawyers would be acquitted. This is a fundamental weakness of the American legal system.
A second con of our system is that it is underfunded and overburdened. Courts have long backups in their caseloads. Public defenders have too many cases assigned to them. These problems make it harder to get things done in a timely manner.